SAS macro to print out change of baseline scores - arrays

Question

I'm looking for a way to print out change of tests scores for each subject with a SAS macro. Here is a sample of the data:
Subject Visit Date Test Score
001 Baseline 01/01/99 Jump 5
001 Baseline 01/01/99 Reach 3
001 Week 6 02/12/99 Jump 7
001 Week 6 02/12/99 Reach 6
002 Baseline 03/01/99 Jump 2
002 Baseline 03/01/99 Reach 4
002 Week 6 04/12/99 Jump 5
002 Week 6 04/12/99 Reach 9
I would like to create a macro that generates the following for each subject:
Subject Visit Date (Days from Baseline) Test Score Change from Baseline Score
001 Baseline 01/01/99 Jump 5
01/01/99 Reach 3
001 Week 6 02/12/99 (42) Jump 7 +2
02/12/99 (42) Reach 6 +3
002 Baseline 03/01/99 Jump 2
03/01/99 Reach 4
002 Week 6 04/12/99 (42) Jump 5 +3
04/12/99 (42) Reach 9 +5
I believe I can just use the INTCK function for the Days from Baseline, but I'm not sure how to print out each test without retaining the 'Subject' and 'Visit' values in each row. Any help would be much appreciated.

Answer 1

You can sort by test and process using a retain for date and score for computing deltas. The print out can be done with Proc REPORT, formatting delta values appropriately.
Example:
data have; input
Subject Visit& $8. Date& mmddyy8. Test $ Score; format date mmddyy8.; datalines;
001 Baseline 01/01/99 Jump 5
001 Baseline 01/01/99 Reach 3
001 Week 6 02/12/99 Jump 7
001 Week 6 02/12/99 Reach 6
002 Baseline 03/01/99 Jump 2
002 Baseline 03/01/99 Reach 4
002 Week 6 04/12/99 Jump 5
002 Week 6 04/12/99 Reach 9
run;
proc sort data=have;
by subject test date;
run;
data for_report;
set have;
by subject test;
retain base_date base_score;
if first.subject then do;
base_date = .;
base_score = .;
end;
if first.test and visit='Baseline' then do;
base_date = date;
base_score = score;
end;
if not first.test then do;
delta_days = intck('days', date, base_date);
delta_score = score - base_score;
end;
run;
proc format;
picture plus low-0 = [best12.] other = '000000009' (prefix='+');
options missing=' ';
proc report data=for_report;
columns subject visit date delta_days test score delta_score;
define subject / order;
define visit / order order=data;
format delta_days negparen.;
format delta_score plus.;
run;
options missing='.';
An alternate report can be more subject-centric:
proc report data=for_report
style(lines) = [just=left fontweight=bold]
;
columns subject visit date delta_days test score delta_score;
define subject / order noprint;
define visit / order order=data;
format delta_days negparen.;
format delta_score plus.;
compute before subject;
subj = catx(' ', "Subject:", subject);
line subj $200.;
endcomp;
run;

Answer 2

Here is one way of doing it. The SQL-step calculates changes from baseline. The case-when-construct is only there to suppress zeroes in the output.
Printing using group-variables in proc report means Subject- and Visit-values are not retained on every line (but note that subject is not repeated each week).
I put the code in a macro, as that was the question. It doesn't really do much, however.
/* Creating test data*/
data testdata;
input Subject $3. #5 Visit $8. #17 Date mmddyy10. #28 Test $5. Score;
format date mmddyy10.;
datalines;
001 Baseline 01/01/99 Jump 5
001 Baseline 01/01/99 Reach 3
001 Week 6 02/12/99 Jump 7
001 Week 6 02/12/99 Reach 6
002 Baseline 03/01/99 Jump 2
002 Baseline 03/01/99 Reach 4
002 Week 6 04/12/99 Jump 5
002 Week 6 04/12/99 Reach 9
;
%macro baselines(dataset=);
/* Adding days from baseline and change from baseline. Please note that the first visit
must denoted as exactly "Baseline"*/
proc sql;
create table changes as
select t1.*, case when t1.date-t2.date>0 then t1.date-t2.date else . end as days
"Days from baseline", case when t1.score-t2.score>0 then t1.score-t2.score else .
end as score_change "Change from Baseline"
from &dataset as t1 left join (select * from &dataset where visit="Baseline") as t2
on t1.subject=t2.subject and t1.test=t2.test
order by subject, visit, test;
/* Printing the dataset. The use of subject and visit as group variables keeps SAS from repeating the values*/
title "Changes based on the dataset &dataset";
proc report data=changes;
column subject visit days test score score_change;
define subject / group;
define visit / group;
run;
%mend;
%baselines(dataset=testdata)